It's kind of the same boat as Everest, honestly. They have considered putting PM back, but the issue is the cost of the tires that propelled it. The DL version was propelled completely differently than Florida's (ours was pulled along by the constant motion of rubber tires actually laid in the track), and originally Goodyear was the sponsor, which meant unlimited supply of tires. They're sort of at a standstill with doing too much to DL's Tomorrowland yet, because that area is going to need another massive makeover, and hopefully that's on the list after Star Wars Land opens up. They don't know whether to replace the attraction with something new/similar, or try to remove as much of the track as possible.